[bultican]

Hello all,
I am a photographer, and make prints using the silver gelatin processes (any photo you have seen from before 1950 is most likely this type of process). 

I need to find a way to cause ions in a silver halide to oxidize and migrate to the surface of the paper.  This is also known as "Silver Mirroring" in the photography world.

The Silver Gelatin Print process is done by taking the film negative and exposing it onto photographic paper.  The paper has a protective ("glossy") layer, which has on it a coat of silver salts (silver chloride mostly, sometimes silver bromide).  When the silver salts are exposed to light, a few atoms of free metallic silver are liberated. These free silver atoms form the latent image. Developing uses solutions that reduce silver halides in the presence of free silver atoms. An 'amplification' of the latent image occurs as the silver halides near the free silver atom are reduced to metallic silver.  The end result is a black and white image.

These types of photos detriorate, over long periods of time, by the silver ions oxidizing and migrating to the surface of the paper, causing a reflective surface ("Silver Mirror").  99.99% of the time, this is not a desired result.  Well, I'm the 0.01 percenter.  I have made photographs of some fine art prints and would like to induce this reaction on the print.

After searching the internet for weeks, I have found very little due to the fact this is mostly an undesired effect.  I have learned, however, that contact with acidic papers over the years can cause this (i.e. keeping the print wrapped in a newspaper), but it will take far too long.  I have also read that hydrogen peroxide, in the form of humidity, can cause oxidization and the humditiy can make it easier for the silver ions to "migrate".  Can anyone validate this hydrogen peroxide claim?

Can someone recommend any methods that could be used to cause the silver ions from the gelatin to oxidize and migrate?

Thank you.

[Borek]

After searching the internet for weeks, I have found very little

I think that can be source of your problem - these are relatively old technologies, internet is not that good when it comes to older things. I would start with an old style classic library, full of thick, dusted books

I seem to remember same effect from some of B&W prints I made back in seventies - but whether it was lousy procedure or faulty paper/developer/fixer I have no idea. At the time it was quite common in Poland that reagents were not following specification. However, that may mean the same process can be reproduced - and I would search old photography books for recipe.

Funny thing - few days ago I bought a real photo postcard from Warsaw, made in twenties - and it lies on my desk, as it arrived earlier today. Darker parts of the image show the effect you mentioned.

[bultican]

Unfortunately, I have looked in libraries and old book stores for this type of info.  The problem is that I have never seen anywhere talk about how to create the effect, it is always about correcting it.  Any article that does talk about how it develops, says that it is from being in contact with acidic rag paper (i.e. newspaper) over many decades.  I obviously would like to expedite the process.

Thanks for the suggestion though, and I will definitely keep an eye out for old photography books.  If it was easy enough to create the effect by accident, maybe there is an easy method after all.

[Borek]

Have you tried to contact Kodak? After all they must have a huge knowledge database about all kinds of photography related processes. Whether they would like to share is another thing, but if you won't try, you will never know.

[bultican]

I have not tried Kodak yet, but may give that a shot.  But I have contacted some photographers that specialize in this type of photography, and over and over again, the problem I run in to is nobody wants this effect, they all want to correct it.  So I thought to start looking into what exactly causes it chemically and see if I could duplicate it.

Right now getting a hold of more photographers or film manufacturers is kind of a backup plan to inducing the reaction.  They keep telling me I should find a special way to print the art prints on an inkjet printer.  Not interested.

[Woofuls]

Somebody did their PhD on what is chemically happening. Check out his website at http://iaq.dk/silvermirror/. You can download his dissertation at http://iaq.dk/silvermirror/dissertation.pdf (Di Pietro, Giovanna. Silver Mirroring on Silver Gelatin Glass Negatives. 2002. Dissertation. Universität Basel). Refer to 4.2.2 in the dissertation for his artificial method.

In addition, somebody else has a method too: Nielsen, U. B. 1993. Silver mirror on photographs. Master thesis. Royal Danish Academy of Fine Arts, School of Conservation.